In many different contexts, there is a need to be able to separate, from liquid flows, matter or bodies accompanying the liquid. To this end, use is made today of different types of filtering or screening apparatuses which, as a rule, are based on the principle that an endless belt provided with filter elements is immersed in the liquid. There are also embodiments in which the filter elements are fixed on two or more endless chains. Moreover, the filter elements are provided with projecting portions which are disposed to lift up the accumulated matter out of the liquid. The projecting portions are generally formed from separate elements.
One problem in prior art apparatuses of this type is that it is difficult entirely to clean the individual filter elements, since they are positioned so close together that, on cleaning, they block one another to some degree or are blocked by devices for lifting up accumulated matter. If the cleaning operation does not function, residual matter on the filter elements will be carried down into the liquid flow behind the filter or screening arrangement and once again pollute the liquid. This is of course a disadvantage.
Another problem inherent in the prior art apparatuses is that a portion of the matter which is separated from the liquid continuously remains in the filter and/or the drive means. In such cases, the risk is imminent that the filter becomes clogged or that the entire apparatus seizes, which may destroy both the drive means and filter components.